[目的] 了解喀斯特地区植被恢复对土壤碳释放的影响,为精确估计区域土壤碳收支变化提供参考. [方法] 以喀斯特峡谷地区典型植被类型(草地、稀灌草丛、灌丛和乔木林地)为研究对象,采用Li-8100便携式土壤呼吸仪对其土壤呼吸、土壤温度和土壤水分进行定位连续观测,系统研究土壤温度(T)和土壤湿度(W)对土壤呼吸速率(Rs)的影响. [结果] (1) 草地、稀灌草丛、灌丛和乔木林4种植被类型土壤呼吸均呈单峰型季节动态,土壤呼吸速率的最大值均出现在夏季,最小值出现在冬季,其土壤呼吸速率变化范围分别为0.73~1.21,1.20~1.48,1.54~2.41,1.86~2.95 μmol/(m2·s);观测期内,土壤呼吸速率均值分别为1.65,2.76,2.45,3.43 μmol/(m2·s). (2) 土壤温度是影响土壤呼吸速率的主导因素,单因素指数模型显示土壤温度对土壤呼吸速率变化的解释能力为72.37%;三次项模型表明土壤水分的贡献率为43.9%.双因素关系模型较好地反映了土壤温度、湿度对土壤呼吸的影响,二者可共同解释土壤呼吸变化的81.5%~91.2%.(3) 土壤呼吸的温度敏感性指数Q10值与土壤温度和湿度均呈显著负相关(p<0.05). [结论] 4种植被类型土壤呼吸及其温度敏感性同时受土壤温度和水分影响,当土壤含水量过低或过高时,土壤温度的主导作用相对减弱,土壤湿度的影响作用加强.
[Objective] The objective of this study is to explorer soil respiration features and its responds to soil temperature and soil moisture under different vegetation in order to provide references for the accurate estimation of payment changes and balance of soil organic carbon. [Methods] Soil respiration rate(Rs) of four typical succession communities including grassland, thin shrub-grassland, shrub land and forest land were observed by using LI-8100 soil carbon flux measurement system to investigate the influences of soil temperature(T) and soil moisture(W) on soil respiration in typical karst regions of Guizhou Province. [Results] (1) The seasonal variations of soil respiration rate of four vegetation types showed a similar unimodal distribution, with the peak occurred in summer and depression occurred in winter. The range of soil respiration rate in four vegetation types was 0.73~1.21,1.20~1.48,1.54~2.41 and 1.86~2.95 μmol/(m2·s), respectively. The average soil respiration rate was 1.65, 2.76, 2.45 and 3.43 μmol/(m2·s) in the observation period. (2) Univariate model indicated that soil temperature and moisture could explain soil respiration variation by 72.37% and 43.9%, respectively. Double factor model suggested that soil temperature and moisture together could explain 81.5%~91.2% of the seasonal variations in Rs. (3) The temperature dependence of soil respiration (Q10) has been widely used in estimating soil respiration rate. Soil temperature and moisture were both negatively correlated to Q10 of four vegetation types. [Conclusion] Soil temperature and moisture together influenced soil respiration rate and Q10 values, and when the soil moisture was too high or too low, the effect of temperature was weakened, and the effect of the soil moisture reinforce.